Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.7 (acetylcholinesterase)
 28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Frog sartorius muscles were treated with an irreversible cholinesterase inhibitor and then incubated in isotonic potassium propionate solution (isotonic KPr). Total and bound, presumably vesicular, acetylcholine (ACh) in the tissue and ACh in the medium were assayed by mass fragmentography, miniature end-plate potentials (MEPPs) were recorded and the end-plates were investigated by electron microscopy. 2. Incubation in isotonic KPr for 30 min stimulated ACh release and concomitantly decreased total and bound ACh. Nerve stimulation for 30 min by trains of impulses (0.1 s trains of 100 Hz, 1 train s-1) in normal-potassium propionate-containing solution had the same effects. 3. When the tissue was incubated in normal-K+ Ringer solution for 3 h, following chemical or electric stimulation, bound ACh recovered to about 75% of the initial value, provided that Cl- ions were present in the medium. In the presence of propionate instead of Cl- ions almost no recovery of bound ACh took place. There was also recovery of bound ACh in the presence of either NO3- or gluconate ions. In NO3- it was the same as in Cl-, but in gluconate it was less than found in Cl- -containing medium. 4. Recovery of total ACh, in contrast to bound ACh, took place even in the presence of propionate ions, showing that extracellular Cl- is not required for the synthesis of ACh. 5. In terminals recovered in normal Ringer solution, many synaptic vesicles were found, but terminals 'recovered' in propionate solution were depleted of vesicles. 6. From these and other results it is concluded that the recycling of synaptic vesicles normally requires the presence of extracellular chloride.
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PMID:The effect of anions on bound acetylcholine in frog sartorius muscle. 278 83

The work is aimed to find out the role of extra- and intracellular Ca2+ in cyclic mechanisms of NO2- and H2O2 metabolism in the stroma cells of endometrium activated by acetylcholine. High activity of Mg2+, Ca(2+)-ATP-ase is characteristic of stroma cells of the endometrium. This activity is tested in the presence of 0.01% of the Triton X-100 (36 +/- +/- 2 mumole Pi/mg of protein for 1 hour). The acetylcholinesterase activity in these systems is equal to 9.8 +/- 0.2 mumole thiocholinebromide/mg of protein for 1 hour. Acetylcholine (10 microM) elevated essentially the concentration of cytosolic Ca2+ in them. It was established, that in the control the suspension of stroma cells produced 1 nmol/NO2-/10(6) of cells, this value being constant for the experimental period of time in the range of 5-60 s. The activation of cells (1 microM acetylcholine + 10 microM Ca2+) results in the appearance of cyclicity (maxima on 5, 15 and 60 s) and 5-fold intensification of NO2- production. The rise of extracellular concentration of Ca2+ up to 0.1-1--10 mM results in essential change of the character of the time dependence of NO2- metabolism and only in inappreciable intensification of the response amplitude. Such a pattern is observed for H2O2: 0.77 mumol H2O2/10(6) of cells in the control, at 10 microM Ca2+ maxima of production on the 5 and 30 s, change of the form of the time response, instead of the amplitude under the increase of concentration of extracellular Ca2+. Preincubation of cells with modifiers endoplasmic reticulum ryanodine, caffeine (1 mM) and heparine (10 mM) results in essential drop of NO2- production and infringement of cyclicity, the effect of ryanodine being more expressed on 5 s, than on 15 s, and heparine--also on 5 s, and on 15 s. Preincubation of cells with methylene blue (10 mM), which inhibits guanilate cyclase, result in considerable intensification of NO2- and H2O2 formation and cyclicity losses. Dynamics of NO2- formation (is controversy) reciprocated with cGMP, whereas nitrosoglutathione production and NO3- tends to saturation in the course of time. Thus, acetylcholine-dependent variations of NO2- and H2O2 concentrations in the suspension of stroma cells depend on the state of extra- and intracellular Ca(2+)-stores, are controlled by cGMP. It may be assumed, that the NO2- production minima are caused by its transfer in NO3- and its binding with glutathione.
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PMID:[Role of extra- and intracellular Ca2+ in changes of NO2- and H2O2 production by endometrium]. 1457 56

Apart from analyses for elemental contaminants in field collected specimens, very little is known about the assimilation, accumulation and toxic effects of inorganic contaminants in reptiles. This study examined the chronic accumulation of Cd in a European lacertid lizard (Podarcis carbonelli) following dietary provision of an environmentally realistic concentration of Cd for 21 weeks. Lizards were provided with Cd that had either been biologically incorporated into crickets, or as Cd(NO3)2 added superficially to crickets just prior to feeding. Among both treatment groups Cd accumulated in tissues in the following order of concentration: gut>liver>kidney>carcass. The majority of the Cd was retained within the gut, and transfer to internal organs was low. Morphological indices, brain and plasma cholinesterase activities, gut and liver metallothionein content, and standard metabolic rate were measured as biomarkers of exposure and effect; however, no differences between control lizards and Cd-treated lizards were observed.
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PMID:Bioaccumulation of Cd by a European lacertid lizard after chronic exposure to Cd-contaminated food. 1746 2

In this work two Zr(IV)-porphyrins were tested as potential acetate-selective ionophores. It is shown that these compounds show increased selectivity towards acetate ion, with selectivity sequence: Cl- < NO3- < SCN- < ClO4- < acetate- < F-, when incorporated into polymeric ion-selective membranes. Among tested ionophores, Zr(IV)-tetra(tert-butylphenyl)porphyrin was found to be the best in terms of response time (20 s) and lower detection limit (2 x 10(-4) M acetate-). Designed electrodes were used as detectors in flow-injection analysis system for acetylcholine determination. Enzymatic hydrolysis was used to generate acetate ions from acetylcholine, employing acetylcholinesterase immobilized on Amberlite. The optimization of enzymatic reactions and flow-injection analysis system configuration were performed and enzyme immobilization procedures have been evaluated. It is shown that resulting flow-injection system exhibits good working parameters, such as reproducibility (standard deviation < or = 3.5%), sampling rate (60 samples per hour) and lifetime (over a week).
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PMID:Metalloporphyrin-based acetate-selective electrodes as detectors for enzymatic acetylcholine determination in flow-injection analysis system. 1946 58

Timolol maleate is a compound used in treatment for reducing increased intra-ocular pressure by limiting aqueous humor production. Decreased erythrocyte deformability (ED), increased activity of erythrocyte acetylcholinesterase (AChE), increased values of nitrosoglutathione (GSNO) and nitic oxide (NO) and decreased plasma levels of NO metabolites, were described in primary open angle glaucoma patients. In healthy human red blood cells (RBCs), timolol is an inhibitor of AChE and induces NO efflux and GSNO efflux from that blood component in lower concentration than those obtained in presence of the natural AChE substrate, acetylcholine (ACh). The signal transduction pathway in RBCs described for NO in dependence of AChE-ACh active complex involves Gi protein, protein tyrosine kinase (PTK like Syk and p53/56Lyn), protein tyrosine phosphatase (PTP) and adenylyl cyclase (AC).The aim of this in vitro study was to verify the effect of timolol maleate in ED, NO efflux and NO derivatives molecules (NOx) like nitrite (NO2-), nitrate (NO3-, peroxynitrite (-ONOO) and GSNO under the presence of PTK, PTP, AC and guanylyl cyclase (GC) enzyme proteins inhibitors.Blood samples from healthy donors were each one divided and were performed aliquots in absence (control aliquots) and presence of timolol or timolol plus each inhibitor and Gi protein uncoupling. No significant differences in erythrocyte NO efflux, GSNO, peroxynitrite, nitrite and nitrate concentrations in response to timolol when compared with the untreated blood samples aliquots were obtained.It was observed an increase in erythrocyte deformability at high shear stresses induced by the simultaneous presence of timolol and band 3 protein dephosphorylation by PTK syk inhibitor. No significant differences where verified in peroxynitrite levels in the blood aliquots in presence of timolol plus each enzyme inhibitor and Gi protein uncoupling in relation to the control aliquots. No variation of GSNO concentration occurs under the presence of timolol and AMGT (PTK lyn inhibitor) besides the significant higher values observed with each one of the other inhibitors. Nitrate concentration increases significantly in all aliquots with timolol plus each one of the inhibitors. The same was observe with nitrite levels with exception of the aliquots with timolol plus AMGT or timolol plus Gi protein uncoupling showing no significant values in relation to the control aliquots.Besides the changes in NO derivative molecules and NO efflux from RBCs obtained in this study with blood samples of healthy donors under the effect of timolol plus each inhibitor of the proteins participants in NO signal transduction mechanism, further analogue studies must be promoted with blood samples of patients with glaucoma or any other inflammatory vascular disease.
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PMID:Timolol effects on erythrocyte deformability and nitric oxide metabolism. 2963 May 36